* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
a {
  text-decoration: none;
  /* 继承父元素的字体颜色 div标签 就是这个值 */
  color: inherit;
}
ul {
  list-style: none;
}
input {
  border: none;
  outline: none;
}
img{
  width: 100%;
  /*  去除图片标签3px的缝隙 */
  display: block;
}
.clearfix {
  zoom: 1;
}
.clearfix:after {
  display: block;
  clear: both;
  visibility: hidden;
  height: 0;
  content: "";
}
